Ambiguous loss is a loss that occurs without closure or understanding.
 This kind of loss leaves a person searching for answers, and thus complicates and delays the process of grieving, and often results in unresolved grief.
 Some examples are infertility, termination of pregnancy, disappearance of a family member, death of an ex-spouse, a family member being physically alive but in a state of cognitive decline due to Alzheimer's disease or dementia, etc.
 An ambiguous loss can be categorized into two types of loss, physical or psychological.
 Physical loss and psychological loss differ in terms of what is being grieved for, the loss of the physical body, or the psychological mind.
 Experiencing an ambiguous loss can lead to personal questions, such as, "Am I still married to my missing spouse?
," or "Am I still a child to a parent who no longer remembers me?"
.
 Since the grief process in an ambiguous loss is halted, it is harder to cope or move on to acceptance from the type of loss experienced.
 There are various types of grief that can occur due to the type of ambiguity experienced and corresponding therapy techniques to address the certain types of grief.
 The overall goal of therapy to cope with ambiguous loss is to overcome the trauma associated with it and restoring resilience.
The widowhood effect is the increase in the probability of a person dying a relatively short time after their long-time spouse has died.
 The pattern indicates a sharp increase in risk of death for the widower, particularly but not exclusively, in the three months closest thereafter the death of the spouse.
 This process of losing a spouse and dying shortly after has also been called "dying of a broken heart".
 Becoming a widow is often a very detrimental and life changing time in a spouse's life, that forces them to go through changes that they may not have anticipated to make for a significant amount of time.
 Responses of grief and bereavement due to the loss of a spouse increases vulnerability to psychological and physical illnesses (Ramadas & Kuttichira, 2013).
The Kübler-Ross model, or the five stages of grief, postulates a series of emotions experienced by terminally ill patients prior to death, or people who have lost a loved one, wherein the five stages are denial, anger, bargaining, depression and acceptance.
Elisabeth Kübler-Ross (July 8, 1926 – August 24, 2004) was a Swiss-American psychiatrist, a pioneer in near-death studies and the author of the groundbreaking book "On Death and Dying" (1969), where she first discussed her theory of the five stages of grief.
Bo's Place, established in 1990, is a nonprofit organization based in Houston, Texas.
 It offers free support programs for children, ages 3 to 18, and their families who have experienced the death of a child or an adult in their immediate family, as well as programs for grieving adults.
 Services include grief support groups offered in English and Spanish, community outreach programs, education and training, and an information and referral line staffed by mental health professionals.
 The referral line assists individuals that have experienced a death as well as family, friends, co-workers or other concerned individuals who want guidance to support the bereaved.
 Bo's Place serves over 1,200 children and adults each year and families stay an average of 14 to 16 months.
An oppari is an ancient form of lamenting in southern india, particularly in Tamil Nadu and North-East Sri Lanka where Tamils form the majority.
 Oppari is a folk song tradition and is often an admixture of eulogy and lament.
 The oppari is typically sung by a group of women relatives who came to pay respects to the departed in a death ceremony.
 It in a means to express one's own grief and also to share and assuage the grief of the near and dear of the diseased.
 Many communities use the oppari to express their grief at a funeral.
 Sometimes professional oppari singers are recruited, but it is a dying practice.
Death Without Denial Grief Without Apology: A Guide for Facing Death and Loss by former Oregon Governor Barbara K. Roberts is a personal narrative of the author's experiences during her husband, Frank's battle with cancer, the final year of his life, and the subsequent years of grieving.
David Kessler (Born February 16, 1959) is an author, public speaker, and death and grieving expert.
 He has published many books, including two co-written with famed psychiatrist Elisabeth Kübler-Ross: Life Lessons: Two Experts on Death and Dying Teach us about the Mysteries of Life and Living" & On Grief & Grieving: Finding the Meaning of Grief through the Five Stages of Grief."
 His first book, The Needs of the Dying is now in a tenth anniversary edition and received praise from Mother Teresa and Marianne Williamson.
Anticipatory grief refers to a grief reaction that occurs before an impending loss.
 Typically, the impending loss is a death of someone close due to illness but it can also be experienced by dying individuals themselves.
 The anticipated grief can be from non-death-related losses such as scheduled mastectomy, pending divorce, company downsizing or war.
The terms delayed grief and unresolved grief are variations of grieving after a loss.
 The meaning of "unresolved grief" is any aspect of grieving that has yet to be resolved.

Question: Who is the author of "On Death and Dying" and co-author of "On Grief & Grieving: Finding the Meaning of Grief through the Five Stages of Grief?"
Answer: Elisabeth Kübler-Ross