Hydrocarbon Processing - May 2021 - 9

J. KRIMMEL, Pinnacle, Houston, Texas

Business Trends
The economics of reliability: An interim report
on the global refining industry
What is reliability? Most people think reliability is simply
a measure of failure, or lack of failure. If something runs for a
longer period without failing, then it is more reliable than something that runs for less time. However, reliability is a measure of
how often something performs when you want it to.
The basis for the author's company's annual and interim
quarterly reports are to explore the connection between reliability and economics so that we can understand how these
key components of modern society intertwine. In doing so, we
begin to see some striking trends and key indicators of opportunity. The goal of these reports is to challenge key industries in
ways never seen before.
Most of the world's industrial facilities buy and sell commodities. Therefore, they have little impact on the price they pay for
their feedstocks or the price they receive for their products. The
nature of every commodity is that producers will fill the market
with enough product until the margins-or profits-for producing that product decrease to a level that no one will produce
more. Inevitably, the balance of supply and demand will separate organizations that are very good at running their facilities
from those that are not. One of the biggest differences between
these two groups is reliability.
Whether discussing jet transportation, power generation,
water processing and treatment, chemicals, mining, oil and gas
production, refining, automotive manufacturing or agriculture,
reliability can mean the difference between excellence and mediocrity, and even profitability vs. bankruptcy.
The author's company's analysts estimate operators of complex facilities around the world spend more than $500 B/yr on
reliability. The author's goal is to view several of these segments
in detail and better characterize the role reliability plays in the
broader economy.
For decades, lean manufacturing has driven companies and
operators to improve runtimes, lower costs and minimize risk
for their facilities. While this push has affected multiple sectors,
no area has produced as much public data as the refining sector,
especially in the U.S. The U.S. Energy Information Administration (EIA) has collected and reported refining data for decades
and, when combined with international reports from the Organization of the Petroleum Exporting Countries (OPEC) and
the International Energy Agency (IEA), among others, the level
of information is unparalleled to other reporting sectors.
Refining reliability overview: Crack spreads as health
indicators. A refiner's financial performance is largely driven

by two variables: the price of raw feedstock (e.g., crude oil) and
the price of finished products (e.g., gasoline, diesel and jet fuel).
As a result, crack spreads-the difference in price between refined products and chosen inputs-are the most useful indicators of the health of the refining sector.
Crack spreads do not account for the cost of running the
plant. Crack spreads ignore costs for items such as the energy to
heat and process the feedstock, the people to operate the plant
and all repair, maintenance and ongoing reliability work.
If we are mostly interested in reliability, then why do we care
about crack spreads? More than 80% of the costs for a refinery are
its feedstock. Crack spreads help us understand what is left over
when we remove a refiner's single largest cost from its theoretical
revenue. This leftover amount is what the refiner uses to cover its
remaining costs, with ideally some profit remaining at the end.
As crack spreads widen, the refiner has more capital available to
invest in its operation or return to its owners. As crack spreads
narrow, refiners have less flexibility and must make difficult decisions about how to deploy their limited capital. Crack spreads
inform about the resources available to invest in best-in-class reliability programs, which is the primary area of interest.
Refining financial landscape. One measure of crack spreads

is shown in FIG. 1. The blue line shows the spot price for Brent-
the international benchmark for light, sweet crude oil. The green
lines show the crack spread between reformulated blendstock
for oxygenate blending (RBOB)-the primary component of
gasoline-and Brent. The solid green line shows the monthly
average crack spread. The dashed green line shows the crack
spread's trailing 1-yr average.
FIG. 1. shows the volatility through which refiners have
learned to manage their business. Since the beginning of 2006,
the smallest monthly average crack spread was $0.01/gal, while
the largest spread was $1.32/gal. In this 16-yr analysis, the crack
spread has averaged $0.40/gal. In comparison, the 2020 yearto-date average is $0.30/gal, a 25% decline from the historical
norm. If we use consumer price index data to account for the
time value of money, the average crack spread from 2006 to the
present increased to $0.46/gal. In constant dollar terms, the
2020 year-to-date spread is then at a 35% discount to the historical average, which explains a large fraction of the prevailing
distress across the global refining sector.
Interesting patterns are apparent in this dataset. Starting
around 2010, aggressive development of U.S. conventional oil
and gas plays brought excess supply to the market. This supHydrocarbon Processing | MAY 2021 9



Hydrocarbon Processing - May 2021

Table of Contents for the Digital Edition of Hydrocarbon Processing - May 2021

Contents
Hydrocarbon Processing - May 2021 - Intro
Hydrocarbon Processing - May 2021 - Cover1
Hydrocarbon Processing - May 2021 - Cover2
Hydrocarbon Processing - May 2021 - Contents
Hydrocarbon Processing - May 2021 - 4
Hydrocarbon Processing - May 2021 - 5
Hydrocarbon Processing - May 2021 - 6
Hydrocarbon Processing - May 2021 - 7
Hydrocarbon Processing - May 2021 - 8
Hydrocarbon Processing - May 2021 - 9
Hydrocarbon Processing - May 2021 - 10
Hydrocarbon Processing - May 2021 - 11
Hydrocarbon Processing - May 2021 - 12
Hydrocarbon Processing - May 2021 - 13
Hydrocarbon Processing - May 2021 - 14
Hydrocarbon Processing - May 2021 - 15
Hydrocarbon Processing - May 2021 - 16
Hydrocarbon Processing - May 2021 - 17
Hydrocarbon Processing - May 2021 - 18
Hydrocarbon Processing - May 2021 - 19
Hydrocarbon Processing - May 2021 - 20
Hydrocarbon Processing - May 2021 - 21
Hydrocarbon Processing - May 2021 - 22
Hydrocarbon Processing - May 2021 - 23
Hydrocarbon Processing - May 2021 - 24
Hydrocarbon Processing - May 2021 - 25
Hydrocarbon Processing - May 2021 - 26
Hydrocarbon Processing - May 2021 - 27
Hydrocarbon Processing - May 2021 - 28
Hydrocarbon Processing - May 2021 - 29
Hydrocarbon Processing - May 2021 - 30
Hydrocarbon Processing - May 2021 - 31
Hydrocarbon Processing - May 2021 - 32
Hydrocarbon Processing - May 2021 - 33
Hydrocarbon Processing - May 2021 - 34
Hydrocarbon Processing - May 2021 - 35
Hydrocarbon Processing - May 2021 - 36
Hydrocarbon Processing - May 2021 - 37
Hydrocarbon Processing - May 2021 - 38
Hydrocarbon Processing - May 2021 - 39
Hydrocarbon Processing - May 2021 - 40
Hydrocarbon Processing - May 2021 - 41
Hydrocarbon Processing - May 2021 - 42
Hydrocarbon Processing - May 2021 - 43
Hydrocarbon Processing - May 2021 - 44
Hydrocarbon Processing - May 2021 - 45
Hydrocarbon Processing - May 2021 - 46
Hydrocarbon Processing - May 2021 - 47
Hydrocarbon Processing - May 2021 - 48
Hydrocarbon Processing - May 2021 - 49
Hydrocarbon Processing - May 2021 - 50
Hydrocarbon Processing - May 2021 - 51
Hydrocarbon Processing - May 2021 - 52
Hydrocarbon Processing - May 2021 - 53
Hydrocarbon Processing - May 2021 - 54
Hydrocarbon Processing - May 2021 - 55
Hydrocarbon Processing - May 2021 - 56
Hydrocarbon Processing - May 2021 - 57
Hydrocarbon Processing - May 2021 - 58
Hydrocarbon Processing - May 2021 - 59
Hydrocarbon Processing - May 2021 - 60
Hydrocarbon Processing - May 2021 - 61
Hydrocarbon Processing - May 2021 - 62
Hydrocarbon Processing - May 2021 - 63
Hydrocarbon Processing - May 2021 - 64
Hydrocarbon Processing - May 2021 - 65
Hydrocarbon Processing - May 2021 - 66
Hydrocarbon Processing - May 2021 - 67
Hydrocarbon Processing - May 2021 - 68
Hydrocarbon Processing - May 2021 - 69
Hydrocarbon Processing - May 2021 - 70
Hydrocarbon Processing - May 2021 - 71
Hydrocarbon Processing - May 2021 - 72
Hydrocarbon Processing - May 2021 - 73
Hydrocarbon Processing - May 2021 - 74
Hydrocarbon Processing - May 2021 - 75
Hydrocarbon Processing - May 2021 - 76
Hydrocarbon Processing - May 2021 - 77
Hydrocarbon Processing - May 2021 - 78
Hydrocarbon Processing - May 2021 - 79
Hydrocarbon Processing - May 2021 - 80
Hydrocarbon Processing - May 2021 - 81
Hydrocarbon Processing - May 2021 - 82
Hydrocarbon Processing - May 2021 - 83
Hydrocarbon Processing - May 2021 - 84
Hydrocarbon Processing - May 2021 - 85
Hydrocarbon Processing - May 2021 - 86
Hydrocarbon Processing - May 2021 - 87
Hydrocarbon Processing - May 2021 - 88
Hydrocarbon Processing - May 2021 - 89
Hydrocarbon Processing - May 2021 - 90
Hydrocarbon Processing - May 2021 - Cover3
Hydrocarbon Processing - May 2021 - Cover4
https://www.nxtbook.com/gulfenergyinfo/gulfpub/HPI-Market-Data-2023-v3
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2024-v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2024
https://www.nxtbook.com/gulfenergyinfo/gulfpub/gas-processes-handbook-2022_v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/gas-processes-handbook-2022
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hp_202212
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2023-v2
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hpi-market-data-2023
https://www.nxtbook.com/gulfenergyinfo/gulfpub/hp_202211
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202210
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202209
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202208
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202207_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202207
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202206_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202206
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202205_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202205
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202204_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202204
https://www.nxtbook.com/nxtbooks/gulfpub/hp_032022
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202203
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202202
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202201
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202112
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202111
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202110
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2022_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2022
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202109
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202108
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_processes_handbook_2021_v2
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_processes_handbook_2021
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202107
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202106
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202105
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202104
https://www.nxtbook.com/nxtbooks/gulfpub/hp_ebooks
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202103
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202102
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202101
https://www.nxtbook.com/nxtbooks/gulfpub/catalyst_handbook_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/catalyst_handbook_2020
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202011
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202010
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2021
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202009
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202008
https://www.nxtbook.com/nxtbooks/gulfpub/refining_processes_handbook_2020
https://www.nxtbook.com/nxtbooks/gulfpub/refining_processes_handbook_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202007
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202006
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202005
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202004
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202003
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202002
https://www.nxtbook.com/nxtbooks/gulfpub/hp_202001
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201912
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201911
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2020_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2020
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201910
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201909
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201908
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201907
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201906
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201905
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201904
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201903
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201902
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201901
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_2018_v2
https://www.nxtbook.com/nxtbooks/gulfpub/petrochemical_2018
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201812
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2019_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hpimarket_2019
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201811
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201810
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201809
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201808
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201807
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201806
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201805
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201804
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201803
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201802
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201801
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201712
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201711
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201710
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201709
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201708
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201707
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201706
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201705
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201704
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201703
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201702
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201701
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2017mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201612
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201611
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201610
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201609
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201608
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201607
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201606
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201605
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201604
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201603
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201602
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201601
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201512
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201511
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201510
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2016mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201509
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201508
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201507
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2015tmsd
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201506
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201505
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201504
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201503
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201502
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201501
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201412
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201411
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2015mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201410
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201409
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201408
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201407
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014petrochemicalprocesses_v2
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014petrochemicalprocesses
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201406
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201405
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201404
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201403
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014calendar
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201402
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201401
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201312
https://www.nxtbook.com/nxtbooks/gulfpub/hp_2014mediaplanner
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201311
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201310
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201309
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201308
https://www.nxtbook.com/nxtbooks/gulfpub/hp_srsguide2013
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201307
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201306
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201305
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201304
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201303
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201302
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201301
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201212
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201211
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201210
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201209
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201208
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201207
https://www.nxtbook.com/nxtbooks/gulfpub/hp_srsguide2012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201206
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201205
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201204
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201203
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201202
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201201
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201112
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201111
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201110
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201109
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201108
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201107_srsguide
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201107
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201106
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201105
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201104
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201103
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201102
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201101
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201012
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201011
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201010
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201009
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201008
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201007
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201006
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201005
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201004
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201003
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201002
https://www.nxtbook.com/nxtbooks/gulfpub/hp_201001
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200912
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200911
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200910
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200909
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200908
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200907
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200906
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200905
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200904
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200903
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200902
https://www.nxtbook.com/nxtbooks/gulfpub/hp_200901
https://www.nxtbookmedia.com